This application pertains to the art of mixing and pumping fluids and, more particularly, to mixing and pumping fluids with apparatus commonly known as an ejector.
Conventional ejectors are operated by injecting a first fluid at a high velocity longitudinally through a convergent-divergent nozzle having a throat where a second fluid inlet is located so that action of the first fluid pumps or draws the second fluid through the second fluid inlet. In such ejectors, the first and second fluids mix slowly because flow is essentially translational, and mixing takes place only in the translational shear layer between the two fluids. A long outlet passage (with large flow losses) is required between the throat and atmosphere to complete the mixing process and to convert high velocity back to pressure before the fluids are discharged to atmosphere.
Other known ejectors or apparatus for mixing and pumping fluids include those disclosed in U.S. Pat. No. 2,565,907, issued Aug. 28, 1951, to Bertin et al. The Bertin apparatus does not have a throat, and does not mix two fluids at a small radius and then discharge the mixed fluids at a larger radius. U.S. Pat. No. 3,306,525 issued Feb. 28, 1967, to Dornier discloses an apparatus wherein the flow radius of the first fluid is not controlled. Therefore, the exit radius of the first fluid is either the same as the inlet radius in FIGS. 2a and 2b, or slightly smaller than the inlet radius in FIG. 1. The swirling flow of the first fluid in Dornier is intended for mixing rather than pumping. In addition, the embodiment of FIG. 1 has essentially laminar flow where the two fluids are mixed. U.S. Pat. No. 3,739,576, issued June 19, 1973 to Chamberlain, discloses an apparatus wherein a first fluid is fed longitudinally into a chamber and is converted into somewhat of a circumferential turbulent flow by vanes located in the chamber. A significant amount of the energy of the first fluid is lost by this arrangement.